Trigger mechanism



1966 F. E. STURTEVANT 3,

TRIGGER MECHANI SM Filed Sept. 28, 1964 5 Sheets-Sheet l 4.4 mmlmx 40 74 INVENTOR. FOSTER E. STURTEVANT BYW,

ATTORNEYS ec. 20, 1966 F. E. STURTEVANT 3,292,492

TRIGGER MECHANI SM Filed Sept. 28, 1964 5 Sheets-Sheet 2 m 1.1mm;

35 INVENTOR.

FOSTER E. STU RTEVANT AT TOR NE YS 1955 F- E. STURTEVANT 3,292,492

TRIGGER MECHANISM Filed Sept. 28, 1964 5 Sheets-Sheet S /G. F 6 Z 20 "3 I \"VljN'lOR.

8 FOSTER E. STURTEVANT BYMy, WWW/2% ATTORNEYS 3,292,492 Patented Dec. 20, 1966 3,292,492 TRIGGER MECHANESM Foster E. Sturtevant, West Hartford, Conn, assignor to Colts his, Hartford, Cor-111., a corporation of Arizona Filed 28, 196%, Ser. No. 399,533 ltl Claims. (65. 89-128) The present invention relates to a new and improved ger mechanism for automatic and semiautomatic guns.

It is a principal object of the present invention to provide a trigger mechanism which facilitates not only single shot and automatic firing of a gun but also provides for the firing of a predetermined burst of shots with a single actuation of the trigger.

An additional object of the present invention is the pro vision of a trigger mechanism which facilitates the repeated firing of a burst of shots upon repeated actuation of the trigger and without further manipulation of the gun by the operator.

Another object of the present invention is to provide an improved trigger mechanism which is capable of providing automatic, semiautomatic and burst firing of a gun by the selective control of the operation of the hammer.

A further object of the present invention is to provide an improved trigger mechanism which exhibits not only the func ional characteristics mentioned hereinbefore but is of simple and compact design so that it is adapted to be applied to guns of current design.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

in the drawings:

MG. 1 is a side elevational view partly in section and partly broken away, showing the trigger mechanism of the present invention incorporated within a gun;

FIG. 2 is an enlarged sectional view taken along the line 22 of FIG. 1 showing the fire control selector mechanism;

FIG. 3 is a view similar to FIG. 1 taken along the line sectional view of the trigger cam on the fire m chanism during an intermediate stage of burst firing; and

PK}. 9 is another view similar to FIG. 7 showing the mechanism during recoil of the bolt carrier when the gun is in a burst firing condition.

Referring now to the drawings in detail wherein like reference characters indicate like parts throughout the tri and has axially disposed therein a firing pin 24 adapted to engage and fire a cartridge positioned within the firing chamber of the gun.

Mounted in and on the lower receiver 14 is a manually adjustable fire control selector 26 including an indicator 2% and a selector handle 30 mounted on the exterior of receiver 14 and a fire control cam 32 integral or rotatably fixed with the indicator 2% and extending transversely of the chamber 12 adjacent the rear wall thereof. As hereinafter more fully described, the control cam 32 provides a plurality of cam surfaces so that by movement of the selector handle 30 so that the indicator 28 points to one of four equally spaced fire control positions, the operator may place the gun in a locked, safety condition, as shown in FIG. 1, or in a condition for full automatic, semiautomatic or burst firing.

The general construction of the trigger mechanism 10 is similar in design and operation to the mechanism disclosed in greater detail in U.S. Patent No. 3,045,555 issued ]uly 24, 1962 to E. M. Stoner and entitled Automatic Trigger Mechanism with Three Sears and a Ro tatable Control Member. However, according to the present invention the trigger mechanism 10 includes a burst control system which provides for the firing of two, three or more shots during a single actuation of the trigger. Broadly, this burst control system provides for the full automatic firing of the gun for a predetermined number of shots and then stops the firing of the gun until the trigger is released and then pulled again for the firing of a similar burst.

Referring now to FIGS. 1 and 3, the trigger 34 of the trigger mechanism id is shown to be pivotally mounted on a trigger pin 36 in such a manner that the downwardly extending finger grip portion 38 of the trigger 34 protrudes outwardly of the receiver 14- for manipulation by the operator. integrally connected to portion 38 of the trigger 34 is an elongated upper portion 49 which includes a fiat generally rectangular lug 42 providing at the forward extremity thereof a trigger sear 44. Immediately rearward of lug 42 is located an elongated groove or trigger well 46 which extends to the opposite end of portion 49 from the trigger sear 44- and defines a pair of trigger cam followers 48.

Located within the trigger well 4a in substantial parallelism to each other and pivotally mounted on trigger pin 36 are a pair of disconnectors 50, 52. The disconnector 50 is substantially identical to the intermediate disconnector disclosed in the abovementioned U.S. Patent No. 3,045,555 while the auxiliary disconnector 52 is of somewhat different design as disclosed in greater detail hereinafter. The disconnectors 50, 52 include forward portions 54, 56, respectively, which overlie the flat lug 42 of trigger 34 and the vertically disposed intermediate sears 58, 60 extending upwardly from the respective disconnectors intermediate the ends thereof. Positioned between the bottom of trigger well 46 and the under side of disconnectors 50, 52 are a pair of compression springs 62, 64- which tend to urge the forward portions 54, 56 of the respective disconnectors into contact with the top surface of lug 42 on trigger 34. On the rearward extremity of the disconnectors 5t 52 are the disconnector cam follower 66 and the auxiliary disconnector cam follower 68, respectively, both of which abut the fire control cam 32 under the bias of compression springs 62, 64.

The trigger sear 44 is biased upwardly in a counterclockwise direction by means of a torsion trigger spring '70 whose upper arm '72 acts upon the lug 42 while the lower arm 7 rests against the bottom of chamber 12. As shown in FIG. 1, the trigger sear 44, acting under this bias, engages a trigger sear abutment 76 on the ham mer '78 and thereby maintains the hammer in a cocked position.

The hammer 78, as best shown in FIGS. 4 and 5, is pivotally mounted on the hammer pivot pin 80 by means of the hammer hub 82 which extends outwardly on both sides of the hammer body 84. Slideably positioned over a portion of the hammer hub 82 is the ratchet type cam wheel 86 which is shown as being provided with a plurality of ratchet teeth spaced at intervals of 60 about the periphery of the cam wheel. In the two-shot burst design illustrated, the shallow ratchet teeth 88 are equally spaced at 120 intervals about the periphery of the ratchet cam wheel 86 while the larger ratchet teeth 90 are positioned intermediate the shallow teeth 88. Each of teeth 90 are provided with a gullet 92 which is closer to the axis of the hammer pivot pin 80 than the corresponding gullets 94 of the teeth 88 as best shown in FIG. 4.

Integral with the body of ratchet cam 86 is a transversely extending cam hub 96 spaced from the hammer hub 82 so as to permit the incorporation therebetween of the small helical one-way clutch spring 98. The spring 98 possesses an inside diameter which is slightly smaller than the diameter of the hammer hub 82 and consequently provides a snug frictional fit therebetween. The spring 98 is provided with an outwardly bent tail 100 which is seated within a slot 102 in the hub of ratchet cam wheel 86. To permit freedom of movement of the first coil of spring 98 it has been found beneficial to make a clearance cut 104 in the cam hub 96 adjacent the slot 102. This cut permits the spring to be bent outwardly on a reasonably large radius thereby adding to the strength of the spring at this point and facilitating manufacturing operations.

A counterclockwise rotation of the hammer hub 82 will cause the spring 98 to tighten and compressively engage the hammer hub and therefore to turn in the counterclockwise direction with the hammer hub 82. Since the spring 98 is fastened to the ratchet cam wheel 86 by means of the cooperation between outwardly bent tail 100 and slot 102, the cam will also turn with the spring and the hammer. However, when the hammer hub 82 is rotated in a clockwise direction, the spring will loosen on the hub 82 and will therefore permit the hub to rotate within the spring without carrying the spring and the ratchet cam wheel 86 along with it in the clockwise direction.

Assisting the ratchet cam wheel 86 in its one-way clutch actuation is the vertically disposed pawl 106 which is fixedly mounted on the forward portion 56 of the auxiliary disconnector 52. As will be appreciated, the pawl 106 is transversely offset from the general longitudinal plane of the auxiliary disconnector 52 so as to mesh with the teeth of the ratchet cam and cooperate therewith in effectuating the one-way clutch action. As can be seen from FIG. 1, the hook 108 of the pawl 106 is forwardly disposed so as to contact the ratchet teeth 88, 90 irrespective of the disposition of the remainder of the trigger mechanism. Accordingly, the hook 108 will at all times prevent the clockwise turning of the ratchet cam wheel 86 by engagement of the ratchet teeth thereby permitting the hammer to rotate clockwise without turning the cam. The hook 108 however, is permitted to follow the camming surfaces of the ratchet teeth by pivotal movement of the auxiliary disconnector 52 about the trigger pin 36 and against the bias of compression spring 64 The hammer 78 is biased in a clockwise direction by the torsion hammer spring 110 which is mounted on the exterior of cam hub 96 and includes an upper arm 112 which acts on the hammer 78 and a lower arm 114 which engages the trigger pin 36. The hammer 78 additionally includes an automatic sear abutment 116 located on the opposite end of the hammer 78 from the hammer hub 82, which abutment is adapted to cooperate with the automatic hammer control 118. The automatic control 118, which is pivotally mounted on pin 120 adjacent the fire control selector 26 and is biased in a counterclockwise direction, includes a tail portion 122 which abuts the fire control cam 32 and a head portion 124 which is maintained by tail portion 122 in a vertical position when the automatic hammer control is inoperative. The head portion 124 is provided with an upper arm 126 which is adapted to be engaged by a shoulder 128 of the bolt carrier 22 during the automatic and burst functions of the weapon and a lower arm 130 which constitutes a sear for engagement with the automatic sear abutment 116.

As can be best seen from FIG. 2, the fire control cam 32 provides a plurality of cam surfaces which act to prohibit or permit the interengagement of various elements of the trigger mechanism. When the fire control selector 26 is placed in the safety position, that is, with the selector handle 30 horizontally oriented and the in dicator 28 facing forwardly, the pair of trigger cam elements 132, best shown in FIGS. 2 and 6, are disposed so that the trigger cam surfaces 134 which are adjacent the periphery of the fire control cam 32 are positioned so as to face the trigger cam followers 48. Thus, when the selector 26 is in the safety position, the trigger cam followers 4-8 engage cam surfaces 132 and are prevented from moving upwardly when the trigger 38 is pulled. Accordingly, the trigger sear 44 is securely held in engagement with the trigger sear abutment 76 thus prevent ing actuation of the hammer 78. In safety position, the forward portions 54, 56 of disconnectors 50, 52 engage the forward lug 42 of trigger 34 and are held out of contact with the hammer 78.

Positioned intermediate the trigger cam elements 132 and constituting a portion of the fire control cam 32 are the disconnector cam 136 and the auxiliary disconnector cam 138. As best shown in FIGS. 1 and 3, cam elements 136 and 138 both possess substantially identical semicircular configurations although the respective orientation of the elements is such that they are displaced relative to each other by with the cam element 38 in a leading position as the fire control cam 32 is rotated clockwise.

As best shown in FIG. 2, the automatic cam element 144 is positioned at the end of fire control cam 32 adjacent the indicator 28 and includes a pair of diametrically opposed peripheral cam surfaces 146 which act against the tail portion 122 of the automatic hammer control 118 to maintain the sear in an inoperative position and out of engagement with the automatic sear abutment 116 of the hammer 78. The inoperative status of the automatic hammer control 118 thus will be maintained when the fire control selector 26 is set in a safety or semiautomatic condition. Disposed between the cam surfaces 146 of the automatic cam element 144 are a pair of notches 148 which permit the inward and counterclockwise rotational movement of the tail portion 122 on the automatic hammer control 118, thereby facilitating the cooperative operation of the automatic sear 130 and the automatic sear abutment 116 when the fire control selector 26 is placed in an automatic or burst firing position.

Located on the opposite end of fire control cam 32 from the automatic cam element 144 is a rotation control member 150 having a plurality of detent recesses 152v located about the periphery thereof for a detent 154 which is biased by spring 156 into engagement with the detent recesses in order to maintain the fire control selector 26 in a predetermined position of adjustment and to prevent inadvertent rotation thereof.

When the gun is loaded and the trigger mechanism 10 is in the cocked position shown in FIG. 1, the gun may be placed in condition to fire by moving the fire control selector out of the safety position and into either the automatic, semiautomatic or burst position.

Referring first to the use of the gun in a semiautomatic firing condition, that is, where a single shot is fired each time the trigger 34 is pulled, the fire control cam 32 is moved from the safety position shown in FIG. 1 through an arc of by appropriate manipulation of selector handle 30. By such movement of the selector 26, the

trigger cam surfaces 134 and the disconnector cam surface 140 are moved out of contact with their respective cam followers thereby permitting the pivotal movement of both the trigger 34- and the disconnector 50 about the axis of the trigger pivot pin 36. The trigger 34, however, is held in a nonfiring position by the action of trigger spring 7tl which biases the lug 42 in a counterclockwise direction thereby maintaining contact between the trigger sear 44 and the sear abutment 76 on the hammer 78. As will be appreciated from a review of FIG. 1, the cam surface 142 is configured so as to cooperate with the cam. follower 68 and maintain the auxiliary disconnector 52 in an inoperative condition out of engagement with the hammer '78 during this entire firing sequence.

Upon pulling the trigger 34 against the bias'of trigger spring 7i), the trigger sear is disengaged from abutment '76 and the hammer "8 is free to move clockwise under the influence of torsion hammer spring Mil so as to contact and actuate the firing pin 24 located within the bolt carrier 22. The actuation of the gun results, as described in greater detail in US. Patent No. 2,951,424, in the rearward movement of the bolt carrier 22 which, in turn, drives the hammer 78 backward in a counterclockwise direction against the bias of torsion spring 110. This causes the intermediate sear abutment 158 located on the hammer body 84 intermediate the ends thereof to engage the intermediate sear of the disconnector 50 which has been permitted to rotate in a clockwise direction by the pulling of the trigger 34. The cooperation of the intermediate sear 58 and the abutment 158 prevents the hammer 7 8 from following the bolt carrier 22 upon its return to firing position so long as the finger grip portion 38 of the trigger 34 is maintained in a pulled or depressed position. The release of the trigger 34 will cause the intermediate sear 58 to release the abutment 158 due to the action of the lug 42 against the forward portion -1- of the disconnector 55). However, the hammer is held in its cocked position since the trigger sear 44 engages sear abutment 76 on the hammer 78 before sear abutment 153 is released by sear 58.

With the trigger mechanism in the cocked condition shown in FIG. 1, the gun may be placed in an automatic firing condition by rotating the fire control selector 26 so that the selector handle 39 is vertically disposed and the indicator 2? is facing upwardly. In this position of selector 235, the fire control cam 32 is oriented so that the trigger cam followers .8 and the tail portion 122 of the automatic hammer control 118 are out of contact with their respective cam elements 132, 144. However, the disconnector cam res and the auxiliary disconnector cam 138 are positioned so that the cam surfaces Mil, 142 contact the respective cam followers 66, 68 and maintain the disconnectors 5d, 52 out of engagement with the hammer sear abutment 158 during the entire automatic firing sequence. Further, prior to pulling the trigger 34, the automatic hammer control 12.8 is positioned in the vertical position by engagement with belt carrier shoulder 128 and the arm res of head portion 1124.

Upon pulling the trigger 34 and the disengagement of trigger sear 54 with sear abutment 7n, the hammer 78 is free to rotate about its pivot pin 89 so as to strike the firing pin 24 to fire the gun. As the bolt carrier 22 is driven rearwardly, the hammer '78 is returned and the arm 126 of the head portion 124 is released from shoulder 1238 of carrier 22 permitting the tail portion 122 to move into the notch MS of the automatic cam element 144 of fire control selector 25. The automatic sear Hil is then free to contact and engage the automatic sear abutment 116 and secure the hammer 78 against clockwise movemerit during the return of the bolt carrier 22 to battery position. However, when the bolt carrier 22 is returned to battery position, the shoulder 1.28 of the bolt carrier 22 contacts the arm 126 of the automatic hammer con trol HS and rotates it clockwise about the axis of pivot pin 120 to immediately release the hammer 78 and fire another round. Thus, so long as the trigger is maintained in pulled or depressed position by the operator, the gun will continue to fire. Upon release of the trigger the trigger sear 44 will move upwardly under the bias of trigger spring so as to contact the sear abutment and prevent further actuation of the hammer '78. As will be appreciated, the hammer is then in the cocked position, shown in FIG. 1 and is ready for refiring.

According to the present invention, the trigger mechanism 10 may also be set so that the gun can fire a predetermined and limited number of shots in a burst during the single actuation of the trigger 34.

Referring now to FIGS. 7 through 9, there is shown the trigger mechanism with the fire control selector 2:5 positioned'for burst firing of the gun; The'oricntation of fire control cam 32 is such that in the cocked position only disconnector cam 136 contacts its cam follower Q6 and maintains the disconnector 50 in an inoperative posi tion during the firing sequence. Upon actuation of the trigger 34, the auxiliary disconnector 52 is free to pivot about the axis of trigger pin 36 as shown in FIG. 7, thus permitting the forward movement of hook 168 on the auxiliary disconnector 52 under the bias of spring on into the deep gullet 92 of ratchet tooth. As mentioned hereinbefore, the one-Way clutch spring which causes the ratchet type cam 86 to rotate in synchronism with the hammer 78, is so constructed that it slips when the hammer rotates to strike the firing pin and the hook 168 on pawl 106 contacts the ratchet tooth 9d preventing the clockwise rotational movement of the ratchet cam 86 with the hammer 78. However, when the hammer 73 is returned, that is, moved in a counterclockwise direction, the spring 98 grips the hammer hub 82 to tighten itself about the hub to rotate the cam 85 in synchronism with the hammer 78. Therefore, the return of the hammer '73 rotates the ratchet cam 86 in a counterclockwise direction and brings the pawl hook 1% of auxiliary disconnector 52 into engagement with the next successive tooth 88, located on the periphery of cam 86. Due to the fact that gullet 94 of tooth 88 is radially offset from the xis of hammer pivot 86 a greater distance than gullet 92, the intermediate sear 69 on the auxiliary disconnector 52 is held so as to prevent the engagement of the intermediate sear 60 with the intermediate sear abutment 15S.

Upon recoil of the bolt carrier 22, the hammer is returned sufiiciently to permit contact between the automatic sear 130 on automatic hammer control 118 and the automatic sear abutment 1116 of the hammer. The return travel of the bolt carrier 22 to the battery position, as shown in FIG. 8, releases the automatic sear 13% from the sear abutment 116 and since the trigger is still pulled and the intermediate sear 65) is prevented from catching the hammer 78 by the engagement of pawl hook Hi3 against the bottom of gullet 94, the hammer 78 will fire a second shot as in full automatic operation.

When the hammer is again retracted by the second recoil of the bolt carrier 22, the ratchet cam 86 again it '11s in synchronism with the hammer 78, thereby bri g l the following tooth 9% into engagement with the hook tee of the auxiliary disconnector 52. As can be seen in FIG. 9, the gullet 2 of tooth 90 permits the movement of the hook 108 to a full forward position thereby positioning the intermediate sear 5% above the intermediate sear abutment 158 on the hammer '78 for engagement therewith causing the hammer 78 to be held in the cocked position and the gun will not fire again until the trigger is released and pulled again. As explained above, the trigger sear 44 will move upwardly a sufficient distance to engage the sear abutment 76 before intermediate sear 69 disengages sear abutment 158 as the trigger is released.

It will, of course, be appreciated that the ratchet cam 86 may be constructed so that three or more shots can be fired during each burst by increasing the number of shal low teeth 88. In this regard, it may be noted that in the illustrated design, the hammer rotates approximately 60 from the firing position to the cocked position. Consequently, when the gun recoils and the lower face of the bolt carrier 22 forces the hammer 78 backwardly and downwardly, there is an overtravel due to the inertia which results from the high speed of the hammer during cocking, as shown in FIG. 9, which ensures sufficient movement of the ratchet cam 86 so as to advance the pawl to the next successive ratchet tooth. It will of course be understood that should the magazine become empty during a two-shot burst so that only one shot is fired, the remaining single shot of the original burst will be fired upon insertion of a new magazine and actuation of the trigger to complete the burst cycle after which the burst will include the number of shots determined by the arrangement of ratchet teeth on the cam wheel 86.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above de scribed will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. A trigger mechanism comprising in combination a hammer mounted for movement between cocked and firing positions; a trigger connected with the hammer for retaining the hammer in a cocked position; burst control means including a cam having gullets of differing depth engageable by a pawl, said means selectively connecting said hammer and said trigger to provide a predetermined sequence of operation wherein said hammer repeatedly moves between the cocked position and the firing position a specific plurality of times; and a fire control selector for engaging said trigger and said burst control means to effect the predetermined sequence of operation.

2. A trigger mechanism comprising in combination a hammer mounted for movement between cocked and firing positions; a trigger connected with the hammer for retaining the hammer in a cocked position; and a burst control including cam means frictionally engaging said hammer for synchronous movement therewith during hammer mounted for movement between cocked and position; a disconnector adapted for movement relative to the trigger and in operative relationship with said cam means to permit a predetermined sequence of operation of the hammer wherein said hammer repeatedly moves between the cocked position and the firing position; and a fire control selector for engaging the trigger and the disconnector to effect the predetermined sequence of operation.

3. A trigger mechanism comprising in combination a hammer mounted for movement between cocked and firing positions; a trigger connected with the hammer for retaining the hammer in a cocked position; and a burst control including cam means mounted in side-by-side relationship with said hammer and connected thereto for synchronous movement therewith between the firing and cocked positions, a disconnector movable relative to the trigger and with said cam means to permit a predetermined sequence of operation wherein said hammer repeatedly moves between the cocked position and the firing position, said cam permitting greater movement of the disconnector upon termination of the predetermined sequence, an automatic control for engaging said hammer during said sequence of operation, and a fire control selector to effect the predetermined sequence of operation.

4. A trigger mechanism comprising in combination a hammer mounted for movement between cocked and firing positions; a trigger connected with the hammer for retaining the hammer in a cocked position; a ratchet cam mounted coaxially with the hammer for movement during hammer movement from the firing to the cocked position; a disconnector movably mounted on said trigger and having means operative with said ratchet cam during movement of the hammer from the cocked position to the firing position to r ate the Cam relative to the hammer; and an automatic control for momentarily retaining the hammer in a cocked position after the trigger is pulled to fire a shot and the hammer is returned to a cocked position, the disconnector being responsive to the rotation of the ratchet cam relative to the hammer to retain the hammer in cocked position until the trigger is released.

5. A trigger mechanism comprising in combination a hammer mounted on a pivot for movement between cocked and firing positions; a trigger mounted adjacent said hammer and engageable therewith for retaining the hammer in a cocked position; a cam mounted on said hammer and operatively connected thereto for synchronous movement therewith between the firing and cocked positions, said cam having thereon a plurality of spaced gullets; and a disconnector mounted on said trigger and having a pawl in operative relationship with, the gullets of said cam to prevent movement of said cam during the movement of said hammer from the cocked position to the firing position, at least one of said gullets permitting greater movement of said pawl than other of said gullets to permit the movement of the disconnector to retain said hammer in a cocked position when said pawl is positioned therein.

6. A trigger mechanism comprising in combination a hammer pivotally mounted for movement between cocked and firing positions and having thereon a trigger sear abutment; a trigger pivotally mounted adjacent said hammer and having thereon a sear engageable with the trigger sear abutment of said hammer for retaining the hammer in a cocked position; and releasable therefrom to provide a predetermined firing sequence; a ratchet cam rotatably mounted in operative relationship relative to said hammer for synchronous movement therewith between the firing and cocked positions, said ratchet cam having a plurality of spaced ratchet teeth defining gullets therebetween a disconnector pivotally mounted for movement relative to the trigger, said disconnector adapter for engagement with said hammer and having a pawl in operative relationship with said ratchet teeth to prevent movement of said cam during the movement of said hammer from the cocked position to the firing position, at least one of said teeth having a gullet which permits greater pivotal movement of said disconnector to cause said disconnector to engage and retain said hammer against further movement until said trigger is released.

7. A trigger mechanism for firing a burst of shots comprising in combination a hammer mounted on a pivot for movement between cocked and firing positions and having thereon a trigger sear abutment, an intermediate sear abutment and an automatic sear abutment; a trigger pivotally mounted adjacent said hammer and having thereon a scar engageable with the trigger sear abutment of said hammer for retaining the hammer in a cocked position; a ratchet cam rotatably mounted on said hammer and operatively connected thereto for synchronous movement therewith between the firing and cocked positions, said ratchet cam having a plurality of spaced ratchet teeth defining gullets therebetween, at last one of said gullets being closer to the pivot than the gullet immediately adjacent thereto; a disconnector pivotally mounted on said trigger for movement relative to the trigger, said disconnector having a pawl in operative relationship with said ratchet teeth to prevent movement of said cam during the movement of said hammer from the cocked position to the firing position and an intermediate sear engageable with the intermediate sear abutment on said hammer for maintaining the hammer in a cocked position when said pawl engages the gullet closest to the pivot; an automatic hammer control for momentarily retaining the hammer in a cocked position during the firing of the burst of shots.

8. The mechanism of claim 7 wherein a manually op erable fire control selector is provided and includes a transversely extending fire control cam provided with a plurality of cam surfaces adapted to engage adjacent portions of the trigger, disconnector and automatic hammer control to determine the operative conditions thereof.

9. A burst fire control system for use in a trigger mechanism comprising a hammer mounted for movement between cocked and firing positions and a trigger having sear means engageable with said hammer for the retention thereof in the cocked position and for releasing said hammer to fire a burst comprising a specific plural number of shots, said system including second sear means engageable With said hammer to stop the same, and means operable by the hammer during the movement thereof from the firing position to the cocked position to render said second sear means effective to engage said hammer after the specific plural number of shots are fired.

10. A trigger mechanism for burst firing comprising in combination a hammer mounted for movement between cooked and firing positions; a cam operatively connected to the hammer for movement during movement of the hammer between the firing and cocked positions; and a References Cited by the Examiner UNITED STATES PATENTS 2,976,771 3/1961 Lambert 89129 2,986,073 5/1961 Godar 89129 3,204,529 9/1965 Silsby 89140 SAMUEL FEINBERG, Primary Examiner.

FRED C. MATTERN, 1a., BENJAMIN A. BORCHELT,

Examiners.

S. C. BENTLEY, Assistant Examiner. 

1. A TRIGGER MECHANISM COMPRISING IN COMBINATION A HAMMER MOUNTED FOR MOVEMENT BETWEEN COCKED AND FIRING POSITIONS; A TRIGGER CONNECTED WITH THE HAMMER FOR RETAINING THE HAMMER IN A COCKED POSITION; BURST CONTROL MEANS INCLUDING A CAM HAVING GULLETS OF DIFFERING DEPTH ENGAGEABLE BY A PAWL, SAID MEANS SELECTIVELY CONNECTING SAID HAMMER AND SAID TRIGGER TO PROVIDE A PREDETERMINED SEQUENCE OF OPERATION WHEREIN SAID HAMMER REPEATEDLY MOVES BETWEEN THE COCKED POSITION AND THE FIRING POSITION A SPECIFIC PLURALITY OF TIMES; AND A FIRE CONTROL SELECTOR FOR ENGAGING SAID TRIGGER AND SAID BURST CONTROL MEANS TO EFFECT THE PREDETERMINED SEQUENCE OF OPERATION. 